//
//  CameraPreviewView.swift
//  Focale
//
//  Author: Simon-Pierre Boucher
//  Contact: contact@spboucher.ai
//

@preconcurrency import AVFoundation
import SwiftUI

/// AVCaptureVideoPreviewLayer host. The session runs on its own queue;
/// attaching it to the layer here is safe and cheap.
struct CameraPreviewView: UIViewRepresentable {
    let session: AVCaptureSession
    /// Changing this re-runs updateUIView once the session has its inputs,
    /// so the rotation lands on a connection that actually exists.
    var isSessionConfigured: Bool = false

    func makeUIView(context: Context) -> PreviewLayerView {
        let view = PreviewLayerView()
        view.previewLayer.session = session
        view.previewLayer.videoGravity = .resizeAspectFill
        applyPortraitRotation(to: view)
        return view
    }

    func updateUIView(_ uiView: PreviewLayerView, context: Context) {
        applyPortraitRotation(to: uiView)
    }

    private func applyPortraitRotation(to view: PreviewLayerView) {
        if let connection = view.previewLayer.connection,
           connection.isVideoRotationAngleSupported(90) {
            connection.videoRotationAngle = 90
        }
    }

    final class PreviewLayerView: UIView {
        override static var layerClass: AnyClass { AVCaptureVideoPreviewLayer.self }
        var previewLayer: AVCaptureVideoPreviewLayer {
            layer as! AVCaptureVideoPreviewLayer
        }
    }
}